1. Field of the Invention
The present invention relates to a load beam for applying load onto a head, a head suspension having the load beam and supporting the head, and a method of forming a load bend in the load beam.
2. Description of Related Art
An example of the head suspension for a hard disk drive is disclosed in U.S. Pat. No. 5,471,734. This head suspension includes a base attached to an arm of a carriage and a load beam supported with the base.
The load beam includes a rigid part and a resilient part. The resilient part is connected to the base so that the load beam is supported with the base like a cantilever. A front end of the rigid part supports a head and the resilient part applies load onto the head. The resilient part includes a load bend and a bend quantity of the load bend determines the load applied to the head.
When a disk is turned at high speed in the hard disk drive, the head of the head suspension slightly flies above the disk against the load applied thereto by the load beam and writes and reads data to and from the disk.
A flying height of the head is dependent on the load applied thereto by the load beam. This load is called as “suspension preload” or “gram load”. An increasing need for high-density magnetic disks requires the gram load to be severely managed.
The gram load has a linear correlation to a bend quantity of the load bend formed in the resilient part of the load beam. This is because the load beam is supported with the base like a cantilever. Controlling the gram load is carried out by strictly controlling the bend quantity of the load bend.
The load bend is generally formed with metal molds to attain target gram load value, and thereafter, the load bend is irradiated with laser beams to precisely adjust the gram load to the target value.
To provide the load beam of the head suspension with precision gram load, the bend quantity must strictly be managed from during the load bend forming process that uses metal molds.
Namely, the metal molds must closely be managed so as to be accurate. This, however, increases the number of metal mold maintenance processes and elongates a manufacturing line suspension time due to the maintenance processes.